1. Field of the Invention
The present invention relates to an image adjuster for adjusting an image projected by a projector having a light source, an electric optical device for modulating a light beam irradiated by the light source in accordance with image information and a projection optical system for enlarging and projecting the light beam modulated by the electric optical device, and an image adjusting method for adjusting an image displayed by an image display having an electric optical device for forming an optical image in accordance with inputted image signal.
2. Description of Related Art
Image display such as a CRT display, liquid crystal display, organic electroluminescence display and plasma display and projection image display such as liquid crystal projector and a projector having a micro-mirror as a modulator has an individual difference on γ characteristics representing tone of displayed image relative to the voltage inputted to the electric optical device for forming an image.
Accordingly, γ correction is usually conducted on the respective image displays for determining γ characteristics of the respective image displays and displaying constant tone image in accordance with the inputted image signal before being shipped.
In order to conduct γ correction of a projector as a projection image display, a predetermined tone signal has been conventionally inputted on a projector to be adjusted step by step and the image projected in accordance with the respective tone signals is measured with a point sensor such as a calorimeter. Base on the measurement result, the input voltage necessary for obtaining tone signal corresponding to the inputted tone signal is calculated to generate a correction data.
The obtained correction data is stored as a lookup table where the tone signal and the corresponding inputted voltage are recorded in a storage of the projector.
When a tone signal is inputted while the projector is actuated, a MPU of the projector searches in the lookup table in the storage to fetch an input voltage in accordance with the tone signal and the voltage is inputted in the electric optical device to display an image, thereby forming appropriate display image in accordance with the tone signal.
However, in order to determine the γ characteristics using the point sensor, the process of measuring the projected image based on a tone signal with the point sensor to generate a correction data and switching to the next tone signal for measuring with a point sensor has to be repeated, so that it takes considerable time for determining the γ characteristics and generating all the correction data. Specifically, in order to determine the γ characteristics, the inputted tone signal has to be compared with the measurement result on at least thirty-three tones, which requires switching and measurement using the point sensor at thirty-three steps.
Further, in an image display such as a projector for forming projected image by modulating a light beam irradiated by a light source, metal halide lamp, high-pressure mercury lamp etc. are used as the light source. However, light-emitting condition of such light source may sometimes be changed and the image projected when the respective tone signals are inputted is influenced by the light-emitting condition of the light source. Accordingly, the respective tone signals may not be compared under the same condition, and the γ characteristics cannot be determined with high accuracy.